Where does Cheryl Cole find the time? She recently wrapped up her first solo arena tour, is preparing for a Girls Aloud 10-year reunion, and has published a 'tell all' biography (big reveal: she sent Simon Cowell a rude text after he declined to salvage her' X Factor' USA gig).

Busy as she is, things may be about to turn a lot more hectic, with reports that Sky is lining her up to host a chat show.

A TV career that came crashing earthward when the official UK national treasure had her extremely public falling out with Cowell two years ago may be about to achieve lift-off once more.

And this time she won't have to sit through hour after hour of rubbish pop to earn her pay cheque.

Though Camp Chezza is keeping mum on this highly unofficial chatter, the rumours have a distinct ring of plausibility. You can easily imagine her perched on a TV-land couch, playing favourite elder sister to the nation.

Cole, at a glance, has all the attributes required of a winning chat show host: the homespun personality, the unaffected air, the ability to convey glamour without seeming off-puttingly exotic.

Should a concrete offer ever materialise from Sky, she may well be tempted to say yes. Hosting your own chat show looks easy -- in the main, your job consists of persuading people even more famous than you to serve up canned anecdotes. What could go wrong?

Lots. It is remarkable how quickly talented, confident, otherwise successful people can shed every vestige of their dignity when shoved behind a desk, wheeled in front of a studio audience and required to fill the expectant silence with their wit.

There have been many, many celebrity talk-show hosts. All but a handful have crawled back to the day job, no doubt wondering how they were ever persuaded to step barefooted on to the sizzling coals of light entertainment in the first place.

You don't have to look very far for evidence of how easily things can go wrong. Just tune into Sky Atlantic and terrify your eyeballs with Russell Brand's talk show, 'Brand X'.

While most would agree that the lanky Englishman is (in limited doses) a charming fellow, on 'Brand X' -- a production of Fox USA -- he is required to put his charisma to uses for which it was surely never intended.

Which is to say, charming Middle America -- a demographic not noted for its appreciation of Anglo dandies with silly beards.

The results are epically toe-curling. In an early episode, Brand plunges into the crowd and fires off a quip about circumcision, only to be met with baffled quiet.

At least nobody stood up and walked out. Which is the fate that reportedly befell Lily Allen's short-lived 2008 talks show for BBC3.

A clumsy attempt at capitalising on the singer's social-media profile, 'Lily Allen and Friends' featured a specially invited audience of online chums and heavyweight guests such as Samuel L Jackson and posh comic David Mitchell.

Hopes for the programme were feverish at the BBC, which was re-branding its controversial digital service and envisaged Lily Allen's show as centrepiece (unabashedly lowbrow BBC3 costs more than €100 million a year to run and many politicians in Britain have called for it to be shut down).

What nobody considered was whether Allen's flirty, gobby persona -- just about tolerable on a three-minute pop song -- would have enough substance to hold together a 30-minute broadcast.

Alas, from the start, Allen -- still grieving after a miscarriage -- seemed out of her depth.

"Everyone really, really wanted it to work for Lily," said one audience member. "She is such a lovely person, but all the jokes fell flat and she seemed very nervous. It just did not work."

Said another witness: "She was halfway through her interview with David Mitchell when she seemed to forget the questions and launched into an attack on all the horrible things people had written about her on online chat forums.

"It was terrible. Even David Mitchell had to remind her not to criticise the very people who would be watching the show."

Similar ignominy was piled upon American comedian Chevy Chase after what is universally agreed to have been a disastrous foray into the chat-show realm in 1993.

A comic institution in the US, it was assumed he would take to the Letterman/Leno format like a guppy to freshwater.

From the start, however, Chase was jarringly ill at ease. His dialogue was stilted, jokes fell flat, and guests, picking up on his nervous energy, seemed to visibly squirm.

Among many low points, the moment he went truly subterranean was an interview with actress Goldie Hawn, during which Chase seemed to intently address, and be mesmerised by, the empty space over her left shoulder.

It was a David Brent sketch unfolding second after excruciating second on live television.

While Chase was an epic disaster (the series was canned after a few weeks), you can understand why Fox took a chance on him.

In contrast, you struggle to wrap your brain around the baffling logic that led to tennis pro John McEnroe fronting a talk show on the same network. Giving him his dues, his TV career did start promisingly when he was a last-minute stand-in for David Letterman. He should probably have left it there because, as the star of 'McEnroe', the career loudmouth was a straight-sets flop.

Over two consecutive weeks he averaged a fairly stonking Nielsen rating of 0.0.

John McEnroe fronting a talk show has 'disaster' scrawled all over it in neon lipstick. As, it's fair to say, did 'The Magic Hour', hosted by basketballer Magic Johnson. The biggest surprise, surely, is that it lasted 40 episodes.

Similarly, one presumes the only person shocked at the flop ratings of 'The Roseanne Barr Show' was Roseanne herself. And was Elvis Costello really that surprised that his Sundance Channel talk show, 'Spectacle', survived only two seasons?

On the other hand, there are celeb talk-show hosts who seem to come undone despite themselves. Always so natural before the cameras on 'The Osbournes', who'd have thought Sharon Osbourne would fail to impress with her own gig?

Admittedly, the news she would be interviewing some guests from her bed did not augur terribly well. Still, it came as a surprise to everyone that she was unable to attune her sassy, cutting personality to the parameters of daytime TV.

Before Cheryl Cole runs wailing for the hills, it ought to be noted that not every celebrity chat show is an unmitigated calamity.

Consider the reinvention of Ellen DeGeneres, once a middling actress, now second only to Oprah in the list of daytime presenters.

She draws three million viewers every morning and, having exited the closet at the peak of her acting career, is credited with helping advance the plight of gay people in America (yes, she also introduced international audiences to Crystal Swing, but who among us is perfect?)

She is not alone. Rosie O'Donnell was a high-achieving actress before moving into talk shows (with the footnote that her latest franchise, 'The Rosie Show', was cancelled last March).

And Jimmy Fallon, regarded as the host most likely to inherit Letterman's prize 11pm slot, was an up-and-coming romantic comedy star until he decided his future lay behind a talk-show desk, rather than on a movie set.

There's a lesson here -- that the best talk-show host is not necessarily the most obvious candidate. Who, for instance, would have thought William Shatner, the ham from beyond space, would, with his addictive 'Raw Nerve' offering, triumph where Sharon Osbourne, Lily Allen and Russell Brand failed?

There's a lesson in here for Sky executives somewhere. Rather than wooing Cheryl, perhaps they should think outside the box a little. If any of them happen to be reading, we're sure we have Jedwards' phone number on us somewhere.